This invention relates to an ultraviolet sensing device and more particularly to a low cost, fail-safe sensor for an utlraviolet water purifier.
Ultraviolet water purifiers normally employ a fail-safe circuit for turning off the water supply in the event of a failure in the purification system, e.g., a burning out of the mercury vapor lamp typically employed for such water purification. Such circuits often employ a photocell specifically designed for the 2537 A peak output wavelength of such mercury lamps. Such special purpose photocells are difficult and therefore expensive to manufacture.
Among the several objects of the present invention may by noted the provision of an ultraviolet sensing device suitable for ultraviolet water purifiers; the provision of such a sensor which is of relatively low cost, which is reliable and which is of relatively simple and inexpensive construction. Other objects and features will be in part apparent and in part pointed out hereinafter.